The manufacture of some electronic devices, including some utilizing radio frequencies, requires the use of electrically conductive film epoxies. These epoxies are used to bond substrates (of various materials) to aluminum chassis that sometimes have milled channels as deep as one inch. The purpose of the channels is to provide a predetermined space for which the radio frequency energy travels. However, laminating substrates in these deep and often intricate channels presents a processing challenge The lamination process must be capable of providing enough heat and pressure to achieve a reliable bond line.
In the past, lamination has been performed with a vacuum equipped oven capable of providing pressure to the components while subjected to appropriate cure temperatures (up to 150 celsius). Although, vacuum offers a consistent means of applying pressure, the pressure is limited. An ideal vacuum will provide approximately 14.7 psi. However, in practice, there is loss and this particular vacuum process provided no greater than 11 psi of pressure. This pressure is insufficient for curing many microelectronic film epoxies. Because of insufficient pressures using the vacuum method, substrates would not bond consistently and often times delaminated or even peeled away from the chassis floor. The immediate effect is a detriment to the radio frequency performance and the longer term implication is a compromise product reliability.
Lamination presses are used throughout the industry for a variety of applications. The platens are typically flat plates used for applying pressure to flat materials. They are not typically used for bonding microelectronic substrates into deep chassis cavities.
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.